This is a complex subject and from my searches it even goes into the meaning of Hebrew words. On one hand, we have verses that prophecy the coming of a New Covenant. Also, the Mosaic Covenant was conditional.
Here's the part from the aforementioned article that pertains to this:
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THE OLD COVENANT WAS TEMPORARY
Jeremiah prophesied that God would make a “new covenant” unlike the old one. The old, however, would not remain side-by-side with the new. “‘Then it shall come to pass, when you are multiplied and increased in the land in those days,’ says the Lord, ‘that they will say no more, “The
ark of the covenant of the Lord.”
It shall not come to mind, nor shall they remember it, nor shall they visit it, nor shall it be made anymore’” (Jer.3:16, emphases added; see also Isa.43:18; 65:17).
The “ark of the covenant” represented the Mosaic covenant. It was the receptacle for the two tablets of the Ten Commandments, the centerpiece of the Mosaic institution. When Jeremiah said that the “ark of the covenant” will “not come to mind,” he was symbolically referring to the Mosaic covenant. It would not come to mind because it would be replaced by another system that would “feed [them] with knowledge and understanding” (Jer.3:15). If the Mosaic covenant would not be remembered, then it would certainly not be in effect.
The Mosaic was not merely limited in duration; it was also limited in location to its Promised Land setting. Moses reminded Israel: “You shall not at all do as we are doing here today—
every man doing whatever is right in his own eyes—for as yet you have not come to the rest and the inheritance which the Lord your God is giving you” (Deut.12:8–9, emphasis added).
Israel was free from many of the legal stipulations as long as it had not yet reached the Promised Land. The fact that the Israelites born during the desert wandering had not been circumcised provides strong evidence of this (Josh.5:5).
The Mosaic covenant was never called “everlasting.” This wasn’t because Scripture seldom describes covenants in general as everlasting. On the contrary, many covenants are so referenced; but
never the Mosaic. The first covenant mentioned in the Bible is the one that was made with Noah (Gen.9:16; Isa.54:9–10) and it was called “everlasting.”
The next covenant was that made with Abraham and subsequently extended to Isaac and Jacob. This too was termed an “everlasting” covenant (Gen.17:19,13; Ps.105:9–10,42; 1Chron.16:15–17).7
The Mosaic covenant was next. This one formed the center of Israelite thought and practice and had center stage throughout the bulk of the Hebrew Scriptures. The Scriptures, however,
never referred to it as “everlasting” or “eternal” or by any other term to that effect.8 The
absence of any such description is profoundly significant given the covenant’s prominent place in Israelite life.
The next covenant was a “perpetual” covenant given within the framework of the Mosaic: the Sabbath (Exod.31:17). The perpetuity of the Sabbath, however, doesn’t suggest that the Mosaic covenant was also perpetual. If the Mosaic covenant had been everlasting, it would have been unnecessary to state that its various features were likewise everlasting. The Sabbath, therefore, was distinguished as perpetual because the Mosaic was not.
The next covenant also was given within the context of the Mosaic. This was the promise to Phinehas of a “covenant of an everlasting priesthood” (Num.25:13). This covenant, as with the Sabbath, stood in contrast to the Mosaic covenant. If the Mosaic had been everlasting, it would have been redundant to offer Phinehas, the Levite, an everlasting priesthood, since all the specifications of the Mosaic already would have been understood as everlasting, including the provision of an everlasting priesthood for the Levites. This covenant with Phinehas was called “everlasting” also because its promise was a done deal, and ultimately would be fulfilled in the priesthood of
all believers (Exod.19:6; 1Pet.2:5).
The next divinely commissioned covenant concerned David. This too was an “everlasting” covenant (2Sam.23:5; Isa.55:3).
The Mosaic covenant is sharply contrasted with the others. Why is a covenant that is so important and central
not regarded as everlasting? Fulfillment of the everlasting covenants depended on one thing—the faithfulness of God to keep His promises. In contrast, the Mosaic depended on the faithfulness of
humankind. Scripture always radically distinguishes the two: God’s faithfulness is certain, while ours is a twisted mess (Ps.14:1)."
Answering Jewish Objections to the New Covenant of Christ - Christian Research Institute
There's also a good discussion of it here:
israel - Was the Covenant made with the Church or does 'Everlasting' mean something other than 'eternal?' - Christianity Stack Exchange
